一正弦交流电的电流有效值为3A，频率为50Hz，则此交流电路的瞬时值表达式可能是（ ）。
A:
B:
C:
D:
A:
B:
C:
D:
举一反三
- 已知逻辑函数<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/db3f3ede53184bb3a37a766a36125eab.png" /> 与其相等的函数为 ____。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/b9f375a5635e41d6911d97ab27bfe708.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/bc54dac1e08f483e88b86be39ec320b1.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/da4ddc58a62f4f35b2fe27419d3e7023.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/9aea77b2ed814b77aed36f7301cd7625.png" />
- 设EI为常数，图示刚架支座C点的水平位移为（ ）。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/2dea6754bc2a40df98d40ddc4d88e4ee.png"/> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/876c3a939abd447fae12277cbbdf2885.png"/> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/9452dbf33f1b42bab8d279978b5294d8.png"/> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/c86de891367447249efb95cf363ee7cf.png"/> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/ba048b2d5eb149fbbe5a7b419903ef5b.png"/>
- 图示刚架的弯矩图中正确的是（）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/96bab3bc877f45e6bc366a1ed24b02e3.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/233d0c9147694598ab60919b0ee7a246.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/f8e911921bb447bdb2e8216ff1bca5cf.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/5c0b8a15b9174de3b636c8ea8a2eb281.png" />
- 图示刚架的弯矩图中正确的是（）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/9e0e3376473a4da185371f58ac37647e.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/860e38197af74aec8db44a11df45c324.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/6ef75cc1379348698b95f277eda55fdd.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/bc248bb6f0cd424eae6b1e66aeb87da6.png" />
- 下列逻辑表示式正确的是____。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/3d0a382ad7af45b29e9047f93676248a.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/28eb85c1fab841768b9d856cb1876018.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/63175bfac29847c4b1ad6359b59006cd.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/cca21ab2476249f78e8e64d81e4dbba0.png" />